Portable illuminating device



Filed Feb. 27, 1962 FIG.

5. D- GURIAN ETAL PORTABLE ILLUMINATING DEVICE 2 Sheets- Sheet l INVENTQRi .520. GOP/AN "=i 65- 37 BY mam/5V4. saw/1272 63 I 9% M0 421 PCRTABLE nwuma'rmc DEVICE F'ile'd Feb. 27 1962 2 Sheets-Sheet 2 INVENTORS. 0. a UR/AA/ flu, JM 401% United States Patent 3,153,745 PORTABLE ILLUMINATING DEVICE Seymour D. Gurian, East Meadow, and Harvey A.

Schwartz, Merrick, N. assignors to Madlgan Electronic Corporation, Carle Place, N.Y., a corporation of New York Filed Feb. 27, 1962, Ser. No. 175,995 3 Claims. (Cl. 315-206) This invention relates generally to illuminating devices and more particularly to an illuminating device which is portable and whichcan be worn on the person, carried. or attached to displaceable objects in order to indicate presence and position in darkened areas.

In the dark it is often difficult and frequently impossible to determine the presence of persons or objects which it is desired to avoid or locate. The darkness in the absence of daylight, especially when there is no moonlight or when atmospheric conditions tend to diminish light, creates serious problems for persons moving about outof-doors. The problem, of course, exists indoors as well.

but the presence of artificial light indoors generally diminishes the hazards.

Particularly endangered under these conditions are persons on foot or traveling on vehicles which do not have available a ready source of power to operate light devices which require high levels of electrical energy to maintain them. Such persons particularly endangered are law enforcement personnel and those ofiicers who attempt to direct moving vehicles by standing in the midst of the vehicles at a traffic intersection. Bicycle riders also have this problem. Often it is desirable to illuminate certain peripheral portions of the vehicles themselves with a low power-consuming, portable illuminating device, such as the wing tips of aircraft, fore and aft sections of small craft on water, bicycles, and many other like objects.

The invention herein disclosed has as its principal object the provision of an illuminating device which is completely self-contained and portable, and which does not require the presence of surrounding light energy in any form.

A further object of this invention is the provision of a portable illuminating device which operates on a flashing cycle to increase the possibility of observation.

An additional object of this invention is to provide an electrical circuit in a portable illuminating device which is low in power consumption and which provides an optimum duty cycle.

Another object of this invention is the furnishing of a portable illuminating device with a rechargeable power pack which can be easily recharged from readily available electrical sources.

Still another object of this invention is to provide a'portable illuminating device which can be formed in a variety of configurations to suit an infinite numberofparticuiar requirements.

This invention utilizes a device which is made up of a phosphorescent material encapsulated in a dielectric and sandwiched between two conductive surfaces; one of which is transparent. The phosphorescent material r'adi-. ates energy in the visible spectrum when excited by alternating electric fields. This phenomenon is known as electroluminescence. The invention utilizes this basic principle in a unique way.

The invention is described herein primarily in the form of a belt and lanyard, or a lnnynrd alone, however. it is understood that the inventive concept is in no way limited to the particular configuration of embodiment disclosed herein and that the description herein is for illustrative purposes only-the invention having utility and novelty in a variety of forms.

The portable illuminating device which is the subject of Oil this invention and the manner of using the same is described herein with particular reference to the drawings, in which:

FIG. 1 is a perspective view of a portable illuminating device constructed in accordance with the teaching of this invention in the form of a belt and lanyard with the outline of a tratiic directing ofiicer wearing the device shown in phantom;

FIG. 2 is a sectional view taken along the line 2-2 in the direction of the arrows as indicated in FIG. 1;

FIG. 3 is a perspective view of a portable illuminating device constructed in accordance with the teaching of this invention in the form of a lanyard with the outline of a bicycle rider wearing the device shown in phantom;

FIG. 4 is a schematic diagram of the electric circuit used to energize the electroluminescent member utilized in the portable illuminating device illustrated in FIG. 1;

FIG. 5 is a diagrammatic showing of two wave forms developed at specific points in the circuit of FIG. 4; and

FIG. 6 is a partially exploded view of the power pack containing the circuit shown in FIG. 4, together with an adapter for use in recharging the storage battery from a specified source.

In FIG. 1 an officer directing trailic is shown in phantom and illustrated generally by the numeral 10. The officer is wearing a portable illuminating device which is indicated generally by the numeral 11, composed of belt 12 and lanyard 13. The belt is generally constructed in the form of an ordinary belt having a buckle 14 for adjusting the diameter thereof and, likewise, the lanyard utilizes buckle 15 to adjust the general diameter of the lanyard. The belt and lanyard are provided with a plurality of electroluminescent panels, each of which is given the numeral 16 in FIGS. 1 and 2, laminated between two strips of flexible plastic material, such as polyvinyl chloride, which completely seals the panels and the associated wiring from the elements.

In FIG. 2 wherein a cross-section of the lanyard is shown, one of the strips of polyvinyl chloride encapsulating an electroluminescent panel 16 is given the numeral 17 and the other the numeral 18. The encapsulating process is one in which the electroluminescent plates are laminated between strips of a polyvinyl chloride material under critical heat and pressure conditions. A satisfactory encapsulating process has utilized heat of about 360 F. and pressure of 500 pounds. There is an upper limit to the amount of heat that an electroluminescent panel can accept without becoming damaged and, depending upon the specific electroluminescent plate, this condition is fixed. It is necessary that either section 17 or 18 be transparent so that the visible light emitted from the plate 16 can be seen. The polyvinyl chloride material also seals the electrical harness which is necessary to connect the electroluminescent plates to the power source'and protects these from the elements. The lanyard is constructed in a simillar manner and the lanyard and belt assembly are fused together at 19 and 20 so that a continuous electrical path is maintained and, likewise, the several electroluminescent panels are electrically connected one to the other in a parallel manner as will appear more clearly from a consideration of the circuit diagram below. At this point it should be noted that the several electroluminescent panels are electrically connected each to the other by two leads. one of which is designated 21 in the figures and the other of which is designated 22. and these are the leads thnt nre also encapsulated by the polyvinyl chloride. The lends also connect the electroluminescent panels to the power pack 23. Power pack 23 will be described more fully below. The power pack contains the electrical circuitry as well as the primary voltage source.

In FIG. 3 an adaptation of the invention is illustrated wherein only the lanyard which therein is given the numcral 13' is shown. The lanyard in the illustration of FIG. 3 is shown being worn by a bicycle rider indicated generally by the numeral 24 and shown in FIG. 3 in phantom. The lanyard 13 is substantially identical in construction to the lanyard 13 having a plurality of electroluminescent panels 16 encapsulated therein with leads 21' and 22' interconnecting the various electroluminescent panels and a power pack 23'. The electrical circuitry, with a slight modification as will appear more fully below, utilized in the embodiment of FIG. 3 is identical with the electrical circuitry utilized in the embodiment of FIG. I.

The alternating current potential required to excite the electroluminescent device shown in FIGS. 1 and 3 is m the region of 125 volts R.M.S.

The device disclosed herein is portable and therefore a self-contained inverter type power supply indicated generally by the numeral 23 in FIG. 1 and the numeral 23' in FIG. 3 is included and this unit contains a D.C. energy source such as a storage battery, for example.

The inverter type power supply converts the low voltage direct current potential from the D.C. energy source into high voltage alternating current needed to stimulate the electroluminescent panels. A relaxation type oscillator is used to generate a signal which exploits the optimum light output while draining a minimum amount of power from the primary energy source. The circuitry utilized is shown in FIG. 4. The circuit of FIG. 4 utilizes the capacitive reactive characteristic of the electroluminescent panel to provide tuned circuitry to which is applied square wave bursts causing the tuned circuitry to ring at a predetermined frequency. The term ring" is used herein to designate that property of an electrically tuned circuit to oscillate at a constant amplitude when a sutficient energy supply is available. In the figures the numeral 25 is used to designate the summation of capacitance found in the belt section and the numeral 26 designates the equivalent of the total capacitance of the electroluminescent panels in lanyard 13. The inductance 27 in the secondary of transformer 28, and the inductance 29 in the secondary of transformer 30, together with the capacitances 25 and 26, respectively, provide two tuned circuits designated in the figures generally by the'numerals 31 and 32, respectively. The tuned circuit 31 is driven through transformer 28 by the circuit associated with P-N-P transistor 33 and its associated circuitry while the tuned circuit 32 is driven through transformer by the P-N-P transistor 34 and its associated circuitry. The N-P-N transistor 35 functions primarily as an electronic switch together with its associated circuitry and mechanical switch 36 is an on-off switch which is utilized to place the device in operation or turn it off. The D.C. voltage battery 37 is shown separated from the other circuitry by switch 36.

Essentially, the purpose of the circuitry is to develop a train of bursts of essentially sinusoidal waveforms such as A in FIG. 5 across the electroluminescent panels. In order to consider the operation of the circuit the analysis will be made for two (2) discrete conditions. The first is the method of generating the envelope, or "on time" to "off time" ratio of the power bursts, such as is indicated by "B" in FIG. 5, while the second describes the method of developing the essentially sinusoidal waveforms within the "on" period, such as is indicated by A" in FIG. 5.

In order to consider the operation of the circuit, it will be assumed that initially the circuit is at rest and the panels are not energized and switch 36 is open separating electrically battery 37 and the remainder of the circuit. Closing switch 36 causes the base of transistor 35 to move positive with respect to its emitter by virtue of resistor 38. This, in turn, causes the collector to move negatively off ground by virtue of the current flow through resistor 46. This, in turn, raises (negatively) the base voltages of transistors 33 and" 34 thuscausing them to conduct heavily. The collectors of transistors 33 and 34 are therefore held just slightly below ground (negalive). The base sides of capacitors 40 and 41 then begin charging to a asymptote, for example, of approximately --8.5 v. The discharging path is from ground through the emitter to collector of transistors 33 and 34 through capacitors 40 and 41 through resistor 39 through the base to emitter junction of transistor 35 to, for example. 9 v. During this time current is also being supplied through resistor 38 to the base of transistor 35.

When capacitors 40 and 41 have expended their stored energy, the voltage across resistor 38 can no longer hold transistor 35 in the full conduction state. Therefore. the collector current of transistor 35 reduces in value thus bringing its voltage closer to ground. At the instant this occurs the base voltages of transistors 33 and 34 are brought closer to ground thus reducing their collector current flow respectively. The incremental collector voltage change caused by this action is regenerated, thus causing transistor 35 and transistors 33 and 34 to cutoff or stop conducting completely. At the instant conduction ceases the collectors of transistors 33 and 34 are at a potential of -9 v. in this example. This, therefore, places the base of transistor 35 at a potential of approximately -l7 v. as the voltage of capacitors 40 and 41 are added to the collector voltage of transistors 33 and 34. The base of transistor 35 then begins to drift toward a ground asymptote via resistors 38, 39, capacitors 40 and 41 and transformer primaries 42 and 43. When the base reaches a critical value (slightly positive of 9 v.) transistor 35 goes into conduction and the entire cycle is repeated. The time during which all transistors are cutoff is the off time" of the pulse train and the time that all transistors are in heavy conduction is the on time" of the train.

In order to develop the essentially sinusoidal waveform during the conduction period, the oscillatory characteristics (ringing) of a tuned circuit is utilized. During the "on time," both transistors 33 and 34 are in heavy conduction. At the instant conduction occurs, a large pulse of current is drawn through each of the primaries of transformers 28 and 30. This causes a rapid flux change in the transformer which is converted to a voltage pulse by the secondary turns and applied to the electroluminescent panels. The capacitances of the electrolumincscent panels resonate with the inductance of the trans former thus causing the current to reverse in the transformer secondary. The time which it takes for this current to reverse is the period of the resonant frequency of the network. This current of opposite polarity to the stimulus is reflected to the primary via the magnetic flux change in the transformers and appears as a voltage of opposite polarity as the initial stimulus. This voltage is passed by capacitors 40 and 41 through to the base of transistor 35"on to its collector with a phase reversal and back to the base of transistors 33 and 34 so as to cause regeneration. The regeneration effect then applies an additional primary stimulus so that the process is continuously repeated so long as there is enough energy in capacitors 40 and 41 to maintain current flow in transistors 35, 33 and 34.

If capacitances of 40 and 41 were held constant, a change of the ratio of resistance 39 to resistance 38 would change the "on" time and, if resistance 39 were made large enough, the circuit would be on continuously.

Resistance 44 and resistance 45 are used to stabilize the I circuitry and to match the characteristics of transistors 33 and 34. Resistor 46 provides the load resistance.

The circuit shown in FIG. 4 is specifically designed to enable its use with the embodiment of the invention shown in FIG. 1 or the embodiment of the invention shown in FIG. 3. The electroluminescent panel capacitance 25 is provided, as stated before, by the belt and that of the lanyard is indicated by the numeral 25. If it were desired to remove the belt to go from the embodiment of FIG. 1 to the embodiment of FIG. 3, the elimination of capacitor 40, transistor 33, transformer 28, resistance 44 and electroluminescent equivalent capacitance 25 would be suificient.

The power pack 23 shown in FIG. 1, and 23 shown in FIG. 3, .which contains the circuitry of FIG. 4, is

packaged in such a way that the power pack can be broken into two distinct parts 47 and 48 which are shown in FIG. 6. A diagrammatic showing of the portion of the power pack designed to contain the circuitry shown in FIG. 4 is indicated in FIG. 6 at 47 with the exception of the electroluminescent panels and the power supply 37. In FIG. 6 an electroluminescent panel, such as panel 25, is illustrated.

The battery is designated in FIG. 6 by the numeral 37 and a charging circuit is shown and indicated by the numeral 49. The charging circuit is a. type frequently used to charge a storage battery from a 115 volt A.C. source and consists of a stepdown transformer 60, a bridge rectifier circuit 61 and a current limiting resistor 62. By means of AC. plug 52 the battery 37 can be charged by plugging into the ordinary wall socket found in the home.

Section 47 and section 48 are connected electrically by contacts 50 and 51 which are also shown on the circuit schematic of FIG. 4. Thus, the battery 37 can be disconnected from the remainder of the circuitry. The plug which is a combination of contacts 50 and 51 is so designed that one half of the plug, such as the members 51 and 50' shown in FIG. 6, can be inserted in the cigarette lighter circuit of an automobile in order to charge battery 37 after sections 47 and 48 have been separated. In order to use the cigarette lighter circuit an adapter 63 is used consisting of polarity diode 64 and lamp current limiter 65. The adapter is placed between the cigarette lighter circuit and contacts 50' and 51'. If, upon connecting the battery to the lighter circuit through adapter 63, lamp 65 lights, the polarity connections are known'to be correct and the battery charges. If lamp 65 does not light, the connection is reversed. This is because some automobiles have a positive ground and some have a negative ground. Thus, the invention disclosed herein can be utilized in a device which is operable over long periods of time and which utilizes a battery which can be charged by the user with the facilities ordinarily available to him. Additionally, since sections 47 and 48 can be separated, the battery portion 48 can be removed from the circuitry portion 47 simply and easily so that a person having a-device constructed in accordance with the invention afiixed to his person and finding that it is necessary to recharge the battery can simply take the necessary section 48 out of the power pack 23 and recharge the battery.

The invention disclosed herein is useful in many forms and can be used on the helmet of a motorcycle user, on a knapsack for hikers, on edge lighting of aircraft, or wherever a portable light device is needed.

Thus, among others, the several objects in the invention as specifically aforenoted, are achieved. Obviously, numerous changes in construction and rearrangement of parts might be resorted to without departing from the spirit of the invention as defined by the claims.

We claim: 1

1. An electrical circuit for use in connection with an electroluminescent panel including in combination a storage battery, an N-P-N transistor, an emitter section of said N-P-N transistor connected to the negative of said storage battery, a collector section of said N-P-N transistor connected through a resistor to the positive of said storage battery, a base of said N-P-N transistor connected through a resistor to the positive of said storage battery, a transformer, a secondaryinductance of said transformer, an electroluminescent panel in parallel with said secondary inductance and providing therewith a tuned circuit, said base of said N-P-N transistor being connected to the negative of said battery through a resistor, a condensor and the primary of said transformer, and a P-N-P transistor with the base thereof connected to the collector of said N-P-N transistor and the collector thereof connected to the negative of said battery through the primary of said transformer.

2. An electrical circuit in accordance with claim 1 in which a predetermined resonant frequency is provided by the combination of said secondary inductance and said electroluminescent panel and electrical energy is supplied by the remainder of the circuit in pulses to enable the combination of said secondary inductance and said electroluminescent panel toresonate at a substantially constant amplitude.

3. An electrical circuit in accordance with claim 1 in which the N-P-N transistor provides a relaxation oscillator and the P-N-P transistor provides a driving circuit to deliver square wave pulses to the primary of said transformer.

References Cited by the Examiner GEORGE N. WESTBY, Primary Examiner. ARTHUR GAUSS, Examiner. 

1. AN ELECTRICAL CIRCUIT FOR USE IN CONNECTION WITH AN ELECTROLUMINESCENT PANEL INCLUDING IN COMBINATION A STORAGE BATTERY, AN N-P-N TRANSISTOR, AN EMITTER SECTION OF SAID N-P-N TRANSISTOR CONNECTED TO THE NEGATIVE OF SAID STORAGE BATTERY, A COLLECTOR SECTION OF SAID N-P-N TRANSISTOR CONNECTED THROUGH A RESISTOR TO THE POSITIVE OF SAID STORAGE BATTERY, A BASE OF SAID N-P-N TRANSISTOR CONNECTED THROUGH A RESISTOR TO THE POSITIVE OF SAID STORAGE BATTERY, A TRANSFORMER, A SECONDARY INDUCTANCE OF SAID TRANSFORMER, AN ELECTROLUMINESCENT PANEL IN PARALLEL WITH SAID SECONDARY INDUCTANCE AND PROVIDING THEREWITH A TUNED CIRCUIT, SAID BASE OF SAID N-P-N TRANSISTOR BEING CONNECTED TO THE NEGATIVE OF SAID BATTERY THROUGH A RESISTOR, A CONDENSOR AND THE PRIMARY OF SAID TRANSFORMER, AND A P-N-P TRANSISTOR WITH THE BASE THEREOF CONNECTED TO THE COLLECTOR OF SAID N-P-N TRANSISTOR AND THE COLLECTOR THEREOF CONNECTED TO THE NEGATIVE OF SAID BATTERY THROUGH THE PRIMARY OF SAID TRANSFORMER. 